BP's Subsea Developments

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 113652, "BP's Subsea Developments: Past Successes and Future Challenges," by Fikry Botros, Cornelia Noel, SPE, David Brookes, SPE, and Robert Perry, BP plc, originally prepared for the 2008 SPE Indian Oil and Gas Technical Conference and Exhibition, Mumbai, India, 4-6 March. The paper has not been peer reviewed. The full-length paper presents an overview of BP's many milestones in subsea projects over the years. The next wave of deepwater and subsea projects will require the development of reservoirs with compound issues. Some of these reservoirs are in remote regions with few offshore host facilities and ecologically sensitive environments. Introduction Currently, BP has approximately 180 subsea wells worldwide, producing approximately 127 190 m3 of oil and gas. This number of wells is expected to double over the next 5 years as the company continues to explore and develop difficult reservoirs in deeper and more-remote hydrocarbon basins. The first subsea wells in the mid-1970s were in the Arabian Gulf. In the 1990s, harsh-environment field developments based on floating production, storage, and offloading (FPSO) vessels were completed in deepwater West of Shetland. Since then, BP has developed and operated subsea fields worldwide with ever-increasing water depths and distances to production hubs. These hubs range from fixed platforms to floating deepwater vessels, tension-leg platforms, FPSOs, semisubmersibles, and spars. Most notable is the series of very large and complex developments in the Gulf of Mexico (GOM), Angola, and Norway. The water depths for the GOM developments exceed 2500 m and in some cases have high-pressure/high-temperature (HP/HT) reservoir conditions of 1000 bar and 130°C, respectively. Off the coast of West Africa, the development of the Greater Plutonio field has been completed successfully by use of an FPSO host, with follow-on plans to develop four additional subsea developments, three of which will be in ultradeepwater Block 31 (2500-m water depth) using modular FPSOs. In Norway, the Skarv harsh-environment FPSO-based subsea development is under development currently. In addition, there are plans to develop a large number of subsea tieback projects to existing facilities, including the record-breaking 72-km Taurt gas development in Egypt and the King-development subsea boosting project in the GOM. Early Developments (1970–1999) North Sea. The five-well Buchan subsea development, started in 1981, is tied back through tensioned-steel vertical risers to a pentagon-style floating rig. In 1988, the two-well Seillean subsea development was the first to produce by means of tensioned risers tied back to a dynamically positioned floating production, storage, and trans port vessel (the forerunner of extended-test and early-production systems). The Magnus field, in 186 m of water, started in 1981, used multiplexed electrohydraulic control systems. The Don field, a 17-km host offset, and the Andrew field with the then-novel 6-km pipeline-bundle tieback concept, followed. The Machar field was completed in 1996 and included the longest black-oil single-leg tieback, approximately 35 km. It also boasted the first subsea pig launcher and subsea metering system.